Page 19 to experiment to find other frequencies inability of the front end tuned cir- to which their scanners may be recep- STANDARD TIME FREQUENCY CROSS REFERENCE cuits to resonate out of their nor- tive. A well calibrated, harmonic -free mal range. signal generator would be helpful. FREQ STATION CALLSIGNS FREQ STATION CALLSIGNS The TV signal format maybe LOST IN THE MAZE OF 2500 FFH JJY MSF OMA RCH 8638.5 DAM unconventional. Chicago's channel WWV ZLF ZUO OBC BIG GOVERNMENT 8650 44, a pay TV service, scrambles 2614 DAN 8721 PPE the video and transmits the audio 2775 DAO 9050 MMO signal using an unconventional for- 3170 OLB5 9996 RWM mat not known to this author. 3330 CHU 10000 ATA BPM JJY LOL MSF Got a question and PRO30 scanners receive Chicago 3810 HD210A RCH RTA WWV can't find the answer? Small channel 44 audio when pro- VPS8 10004 RID and medium -sized companies 3842 grammed for 510.4875 or 510.5875 DAM FTK77 now have a representative in 4265 10775 MHz. 4286 VWC 11440 PLC Washington, thanks to the Commerce Department's Office 4291 ZSC 12000 VNG Technical Explanation 4298 CCV 12008 EBC of Business Liaison. "ROAD - 4500 VNG 12135 *AM What's happening is that an injection MAP" will either find the 4525 NMO Y3S 12307 OBC signal with multiple constituent fre- answers to your questions or 4996 RWM 12724 ZSC quencies is being being fed to the direct you to the person or 5000 ATA BSF HD210A IAM 12745 VW C mixer stage. agency who can. RCH DAM Write them at ROADMAP, IBF JJY LOL MSF 12763.5 To hear the audio from TV channel 32 ZUO Office of Business WWV 13020 VPS60 (583.75 MHz), the PRO30 is set to Liaison, NMO U.S. Dept. of Commerce, 5004 RID 13655 456.5375 MHz. At this setting, the Washington, DC 20230, or 5870 NAM 13873 FTN87 local oscillator/tripler chain is injecting YVTO call 202/377 -3176 to put you 6100 14657.5 NMO a signal into the mixer stage at: 6475.5 DAM 14670 CHU on the right. track! 6840 EBC 14996 RW M 456.5375 - 10.7 7335 CHU 15000 ATA BPM BSF = 445.8375 MHz. 1 7428 FTH42 JJY LOL WWV BOOST WEAK 7500 VNG 15004 RID This 445.8375 MHz signal is the out- 7600 HD20A 16180 NAM put of a frequency tripler, whose input SIGNALS 8000 JJY 16980.4 DAM frequency is: 8090 NAM 17018 ZSC Get clearer distant reception 445.8375 / 3 8167.5 LQB9 17096 VPS80 using ACT -1 POWER 8461 ZSC 17550 LQC20 = 148.6125 MHz. ANTENNA instead of scan- 8473 4PB 20000 WWV But, in addition to this 3rd harmonic, ner's built -in whip. This corn - ZSC pact 21 - inch antenna has 8539 VPS35 22245 there seems to be a 4th harmonic com- 8542 PKI 22536 VPS22 integral preamplifier, gives ponent present: up to 15 dB gain (30 times as NMO 8558 CCV 22593 strong), plus all the advantages 4 (148.6125) of a high antenna away from = 594.4500 MHz, noise pickup. Often outper- forms much larger outdoor 512 657 MHz RECEPTION antennas! Easy to Install on which when mixed with a signal on any vertical surface indoors ON YOUR SCANNER 583.75 MHz (channel 32), produces a or out. No mast required. 10.7 MHz IF: Covers all bands: 30-900 MHz. Bob Parnass, AJ9S ferent programmed settings: 483.7125 Complete with 50 ft. cable, ready to plug into scanner. AT &T Bell Laboratories for TV channel 38, and 456.7125 for 594.4500 - 583.750 +12V power obtained directly TV channel 32 (Bearcat and Radio = 10.7 MHz from most radios. Shack scanners use different intermedi- Articles in Monitoring Times and ate frequencies). Popular Communications have Othe Frequencies Possible described how one may "trick" various By checking the arithmetic, I've con- Although the scheme described in this ACT 1 POWER ANTENNA, scanner radios into receiving frequen- cluded that the same mechanism per- article requires no scanner modifica- - cies they were not designed to receive. mits out of band reception on all these tions or additional hardware, a multi- ONLY $79 + $3 S & H These tricks fall into 2 categories: scanners. ple injection scheme forms the basis 1. Exploiting a bug in the receiver's for a product already familiar to The Method microprocessor firmware by scanner enthusiasts, the Grove "Scan- entering a particular series of In the formulas that follow, all fre- verter." HEAR THE keystrokes. quencies are in units of Megahertz. The Scanverter, a novel 216 - 420 To listen on a frequency U between NEW 2. Exploiting the receiver's finite MHz converter, makes use of multiple BANDS 512 and 657 MHz, tune your radio to: image rejection by listening to injection frequencies to accomplish ON YOUR SCANNER simple images (e.g. to listen to what Bob Grove terms "band stack- Converts out -of -band signals to vhf or uhf 3(U) - 7(1F) frequency F, tune the receiver to ing". In the Scanverter, a local oscilla- scanner bands. Cables provided. Simply 4 plug into scanner. F + 2 * [the intermediate fre- tor produces a signal rich in harmon- quency]). ics. This signal is fed into a where IF is the intermediate frequency broadband mixer along with signals This article describes a third tech- of the receiver. from the antenna, causing several fre- nique, which permits listening in the Conversely, if you hear a strange sig- quencies to be received at each setting 512 - 657 MHz range (UHF television nal when your UHF radio is tuned to of the attached scanner. channels 21 through 44) using radios T MHz, you may be simultaneously designed to receive the 402 - 512 MHz The ability to receive TV signals on a listening to the frequency of: range. The technique uses multiple scanner is usually of little value, but 5 MODELS AVAILABLE: there may be ways of using this multi- 806 -894 MHz New Land Mobile Band injection frequencies, and requires no 400 -420 MHz Federal Government & FBI 4(T) - 7(IF) receiver modification or additional ple injection phenomenon to receive 240 -270 MHz Navy /Air Force Fleet Satellites hardware. 3 bands other than 512 - 657 MHz. I 135 -144 MHz Weather & Geophysical recall receiving the 787.75 MHz audio Satellites 1 discovered my that Radio Shack When using this technique to receive from TV channel 66 somewhere on a 72 -76 MHz Industrial & Radio Control PRO30 scanner receives the audio TV audio on a scanner, the signal may BC100 once! ONLY $88 + $3 S & H from TV channel 38 (619.75 MHz) be weak or distorted because: when the radio is programmed for A simple scanner modification may be Scanner Preamps also available The bandwidth of a TV audio sig- 483.5375 MHz, and from channel 32 - possible that purposely distorts the nal exceeds that of the IF filtering a (583.75 MHz) when programmed to injection signal in way that produces Order by phone or mail. Use credit card, in the typical scanner. 456.5375 MHz. This is also true for both the fundamental frequency and check, COD. Or send $1 for complete catalog by return mail. the Radio Shack PRO2020 scanner. -A typical scanner radio is not as its second harmonic. Theoretically, could cause a scanner with a 10.7 sensitive in the 512 - 657 MHz this Bearcat BC100, BC210, and BC350 420 - range as it is on the frequencies for MHz IF and 512 MHz coverage, scanners can also receive UHF TV sig- which it was designed, due to the to be receptive to signals in the 807.9 - 65 -K MOUL ROAD nals on odd frequencies, but at dif- 991.9 MHz band. Readers are urged HILTON NY 14468 -9535 Phone: 716- 392 -9430

www.americanradiohistory.com